DE102017202877A1 - Process for producing a honeycomb structure - Google Patents

Abstract

A manufacturing method of a honeycomb structure containing a cordierite component is disclosed in which, in a case of using a porous silica powder as an inorganic pore-forming agent, it is possible to minimize a kneading material / water ratio and inhibit the generation of partitioning cracks and the like. The production method of the honeycomb structure includes a raw material-producing step of adding the porous silica powder as the inorganic pore-forming agent to a molding raw material and kneading the molding raw material to prepare the kneaded-molding raw material, an extrusion step for extruding the obtained molding raw material, to form a honeycomb formed body, and a firing step for firing the extruded honeycomb formed body to include a honeycomb structure 1 containing a cordierite component, which becomes a plurality of honeycombs 3, the passageways for a fluid, and from an end face 2a to the first and an amount of the oil to be absorbed to be absorbed by the porous silica to be added to the molding raw material is in a range of 50 to 190 ml / 100 g, and a BET specific surface area of the porous silica lies in an area of 340 up to 690 m2 / g.

Description

The present application is based on JP-2016-037845 filed on 29.2.2016 with the Japanese Patent Office, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a production method of a honeycomb structure, and more particularly, to a production method of a honeycomb structure in which it is particularly possible to suppress the generation of partitioning cracks during production of a cordierite honeycomb structure containing a cordierite component.

Description of the Related Art

Heretofore, ceramic honeycomb structures have been used in wide applications of an automobile exhaust gas purifying catalyst carrier, a diesel particulate filter, a heat storage device for a combustion device, and the like. Here, the honeycomb structure is manufactured by preparing a molding raw material (wrought material), desirably extruding the material in the form of a honeycomb by means of an extruder, and further firing an unfired cut, dried and end-face finished honeycomb formed body at a high temperature.

Particularly, in recent years, a cordierite honeycomb structure (hereinafter simply referred to as "honeycomb structure") containing a cordierite component consisting of three components of silicon, aluminum and magnesium has been produced.

The cordierite component has characteristics that its coefficient of thermal expansion is lower than that of an alumina material and that the cordierite component has excellent thermal shock resistance and durability. Therefore, the honeycomb structure is applied to a wide field of the car exhaust gas purifying catalyst carrier and the like.

In producing a porous ceramic body such as the above honeycomb structure, an operation of adding powder of porous silica or porous silica containing powder (hereinafter referred to generally as "porous silica powder") as an inorganic pore-forming agent becomes a mold Raw material, kneading the molding raw material, and extruding the kneaded-form raw material (see Patent Document 1).

• [Patentdokument 1] WO 2005/090263

When the porous silica powder is used as the inorganic pore-forming agent, there is an advantage over the resin powder or carbon powder formerly used as the inorganic pore-forming agent in that it is possible to suppress the generation of carbon dioxide or a poisonous gas. Further, the porous silica powder contains a combustible fraction smaller than that of the resin powder or the like, and therefore, it is possible to shorten a burning time.

• [Patent Document 1] WO 2005/090263

BRIEF DESCRIPTION OF THE INVENTION

However, it is known that the above porous silica powder has water-absorbing properties (or moisture-absorbing properties). Therefore, water added to a mold raw material could be trapped in the silica powder, or water in the air could be absorbed by the silica powder. As a result, a ratio of water (a kneading material / water ratio) to be taken up into a kneading material tends to increase over that of conventional resin powder or the like.

In a process for drying an extruded honeycomb molded article, a large amount of water evaporates in the kneading material as the kneading material / water ratio increases. As a result, partitions of the honeycomb formed body could shrink and thereby be deformed. Consequently, it is feared that as a result of the generation of defects such as "partitioning cracks" in which parts of the mesh-like partition walls are cut, a final product quality of a honeycomb structure deteriorates.

In order to overcome such problems, in view of the above circumstances, the present invention has been developed and an object thereof is to provide a manufacturing method of a honeycomb structure containing a cordierite component which makes it possible in a case of using porous silica powder as an inorganic pore-forming agent is to minimize a Knetwerkstoff / water ratio and to prevent the formation of partitioning cracks and the like.

• [1] Herstellungsverfahren einer Wabenstruktur, enthaltend einen Rohmaterial-Herstellungsschritt zum Zusetzen von Pulver aus porösem Siliciumdioxid als anorganischem Porenbildner zu einem Form-Rohmaterial und Durchkneten des Form-Rohmaterials, um das durchgeknetete Form-Rohmaterial herzustellen, einen Strangpressschritt zum Strangpressen des erhaltenen Form-Rohmaterials, um einen Waben-Formkörper zu bilden, und einen Brennschritt zum Brennen des stranggepressten Waben-Formkörpers, um die eine Cordierit-Komponente enthaltende Wabenstruktur, welche eine Vielzahl von Waben, die Durchgangskanäle für ein Fluid werden und sich von einer Stirnseite zu der anderen Stirnseite erstrecken, definierende Trennwände aufweist, zu bilden, wobei eine Menge von dem dem Form-Rohmaterial zuzusetzenden porösen Siliciumdioxid zu absorbierenden Öls in einem Bereich von 50 bis 190 ml/100 g liegt und eine spezifische BET-Oberfläche des porösen Siliciumdioxids in einem Bereich von 340 bis 690 m²/g liegt.
• [2] Herstellungsverfahren der Wabenstruktur nach dem obigen Punkt [1], wobei eine Rohdichte des porösen Siliciumdioxids in einem Bereich von 0,15 bis 0,64 g/cm³ liegt.
• [3] Herstellungsverfahren der Wabenstruktur nach den obigen Punkten [1] oder [2], wobei ein 50%-Partikeldurchmesser (D₅₀) des porösen Siliciumdioxids in einem Bereich von 4 bis 24 μm liegt.
• [4] Herstellungsverfahren der Wabenstruktur nach einem der obigen Punkte [1] bis [3], wobei eine Waben-Porosität der Wabenstruktur in einem Bereich von 40 bis 55% liegt.
• [5] Herstellungsverfahren der Wabenstruktur nach einem der obigen Punkte [1] bis [4], wobei in dem Brennschritt das poröse Siliciumdioxid geschmolzen wird, mit einer anderen in dem Form-Rohmaterial enthaltenen Komponente reagiert, um in Cordierit umgewandelt zu werden, und einen Teil der Wabenstruktur bildet.

According to the present invention, there is provided a honeycomb structure manufacturing method for achieving the above object.

• [1] A production method of a honeycomb structure, comprising a raw material-producing step of adding porous silica powder as an inorganic pore-forming agent to a molding raw material and kneading the molding raw material to prepare the kneaded-molding raw material, an extrusion step of extruding the obtained molded article. Raw material to form a honeycomb formed body, and a firing step for firing the extruded honeycomb shaped body to the honeycomb structure containing a cordierite component, which are a plurality of honeycomb, the passageways for a fluid and from one end face to the other Extending end face having defining partitions, wherein an amount of the oil to be absorbed in the porous silica to be added to the molding raw material is in a range of 50 to 190 ml / 100 g and a BET specific surface area of the porous silica is in a range of 340 to 690 m ² / g li egt.
• [2] The production method of the honeycomb structure according to the above item [1], wherein a bulk density of the porous silica is in a range of 0.15 to 0.64 g / cm ³ .
• [3] The production method of the honeycomb structure according to [1] or [2] above, wherein a 50% particle diameter (D ₅₀ ) of the porous silica is in a range of 4 to 24 μm.
• [4] The production method of the honeycomb structure according to any one of the above [1] to [3], wherein a honeycomb honeycomb porosity is in a range of 40 to 55%.
• [5] The production method of the honeycomb structure according to any one of the above items [1] to [4], wherein in the firing step, the porous silica is melted, reacts with another component contained in the molding raw material to be converted to cordierite, and Part of the honeycomb structure forms.

According to a manufacturing method of a honeycomb structure of the present invention, it is possible to obtain the honeycomb structure which stabilizes a product quality without causing deformations such as breakage cracks during drying of a honeycomb formed body, providing a high light-off performance and improving a cleaning efficiency ,

BRIEF DESCRIPTION OF THE DRAWINGS

1 Fig. 12 is a perspective view schematically showing an example of a honeycomb structure of an embodiment of the present invention;

2 Fig. 10 is a plan view schematically showing the one example of the honeycomb structure;

3 Fig. 12 is a graph showing a relationship between an amount of oil to be absorbed and a specific surface; and

4 is a graph showing a relationship between a porosity and a Knetwerkstoff / water ratio.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of a manufacturing method of a honeycomb structure of the present invention will be described in detail with reference to the drawings. It should be noted that the manufacturing method of the honeycomb structure of the present invention is not limited to the following embodiment, and various design changes, modifications, improvements, and the like may be made thereto without departing from the gist of the present invention.

1. Honeycomb structure and manufacturing method of the honeycomb structure

A honeycomb structure manufactured by a manufacturing method of the honeycomb structure of the present embodiment 1 contains, as in 1 and 2 shown a honeycomb body 5 with lattice-like partitions 4 containing a variety of honeycombs 3 define which passageways for a fluid form and move from one end face 2a to the other end 2 B extend, and one around the honeycomb body 5 arranged around peripheral wall part 6 and has a substantially round columnar shape.

The honeycomb structure 1 is a cordierite honeycomb structure containing as a kind of porous ceramic material a cordierite component consisting of three components of silicon, aluminum and magnesium, which are constituent elements. It should be noted that there is no particular restriction on ratios of the respective components of the cordierite component, but the cordierite component is usable, in which, for example, when an overall ratio in a case of converting the above three components into oxides is 100% , Silica is in a range of 50% and above, alumina is in a range of 15 to 45%, and magnesium oxide is in a range of 5 to 30%.

Porous silica powder (not shown) is added in a predetermined range to a molding raw material containing the above cordierite component, and a kneaded molding raw material is produced (a raw material producing step). Here, as the powder of porous silica, a silica powder of an intermediate form (amorphous silica powder) is suitably used, and specifically, a silica gel or the like is usable. It is to be noted that as a porous silica-containing mixture, a mixture containing inter-formed silica is suitably usable.

The kneaded-form raw material is extruded using a known extrusion press to obtain a honeycomb shaped article of a desired shape (an extrusion step). Thereafter, the honeycomb formed body is dried, introduced into a firing furnace set at a predetermined firing temperature, and then fired (a firing step). Consequently, the honeycomb structure becomes 1 with the partitions 4 which are the honeycombs 3 define which are the passageways for the fluid and from the one end face 2a to the other end 2 B extend, manufactured. Here, no particular limitation is imposed on the firing temperature, but the temperature may be set in a range of, for example, 1200 ° C to 1300 ° C.

Here, the molding raw material for use besides the above cordierite component and the above porous silica powder may contain another component. For example, the molding raw material may contain a natural raw material of kaolin or talc or a synthetic raw material of alumina or aluminum hydroxide or various other components. However, it is necessary to maintain the above composition of the cordierite component, and as long as this condition is satisfied, the above addition of the other component can be dispensed with.

Further, in the firing step for firing the "other component" in the molding raw material, e.g. The above natural raw material or the above synthetic raw material, and the porous silica powder at a high firing temperature, the component and the powder react to be converted into the cordierite composition. In this case, a part of the porous silica is melted and consumed as silica forming part of the cordierite component.

Further, the porous silica powder to be added to the molding raw material in the raw material manufacturing step in which an amount of oil to be absorbed is set in a range of 50 to 190 ml / 100 g and a BET specific surface area in a range of 340 is set to 690 m ² / g. That is, in the production method of the honeycomb structure of the present embodiment, properties of porous silica as an inorganic pore builder to be added to the molding raw material, which becomes a starting material, are combined by combining two parameters of "amount of oil to be absorbed" and "BET specific surface area "Fixed.

As a result, it is possible to minimize a water ratio of the kneaded-form raw material (a kneading material / water ratio). Consequently, even in a case of using the porous silica powder, it is possible to suppress shrinkage and deformation of the partition walls during drying, and it is possible to prevent generation of partition wall cracks.

Here, the amount of the oil to be absorbed determines the amount of oil to be absorbed by a powder body under constant conditions, and the amount of the oil relative to 100 g of the powder body is represented by a volume (ml) or an oil weight (g). Specifically, the amount is determined by means of an in JIS K5101-13-1 (or JIS K5101-13-2 ).

Further, specifically, a sample in the form of the powder body whose weight is accurately measured (in this case, porous silica) is placed on a measuring plate, and not less than four or five drops of oil (linseed oil) are brought out of a buret at one time dripped a middle of the sample.

Furthermore, the entire sample is kneaded sufficiently with a spatula after each trickling. This operation of dribbling the oil and kneading the sample is repeated until the entire sample becomes a hard cement block. Thereafter, the dripping of the oil from the burette is changed so that each time a single drop of oil is dripped, and the sample is kneaded accordingly with the spatula. Further, the sample may be spirally wound at the last drop by means of the putty knife, and this state is defined as an end point of the measurement.

When the end point is reached, the amount of dripped oil on the burette is read and a volume (ml) of the oil per 100 g of sample is given by equation (1), where O _{1 is} the amount of oil to be absorbed (ml / 100 g) , V is a volume (ml) of the spent linseed oil and m is a weight (g) of the sample, calculated as follows: O ₁ = (100 × V) / m equation (1)

It should be noted that in a case of indicating the weight (g) of the oil for 100 g of the sample, the amount of the oil to be absorbed is given by Equation (2), in which O _{2 is} the amount of the oil to be absorbed (g / 100 g ), V is the volume (ml) of spent linseed oil and m is the weight (g) of the sample, calculated as follows: O ₂ = (93 × V) / m equation (2)

On the other hand, the BET specific surface area may be, for example, according to the description of JIS R1626 (a method for measuring a specific surface area by a gas adsorption BET adsorption method of a fine ceramic powder body). Specifically, a sample (porous silica) is placed in an adsorption cell, the cell is evacuated while heating the cell, whereby gas molecules adsorbed on the surface of the sample are removed, and a weight of the sample is measured.

Thereafter, a nitrogen gas is passed through the adsorption cell in which the sample is enclosed. As a result, nitrogen is adsorbed on the surface of the sample, and further, an amount of the nitrogen gas flowing therein is increased, whereby the gas molecules form a plurality of layers on the surface of the sample.

At this time, by plotting the above process as a change of an adsorption amount with respect to a pressure change, a graph is prepared, and from the obtained graph, by means of a BET adsorption isotherm equation, an amount of the gas molecules to be adsorbed only at the surface of the sample is obtained. Incidentally, with regard to nitrogen molecules, an adsorption-occupying area is already known, and therefore, based on the amount of the gas molecules to be adsorbed, a surface of the sample can be obtained.

Further, as for the porous silica for use in the production method of the honeycomb structure of the present embodiment, a bulk density is in a range of 0.15 to 0.64 g / cm ³ , a value of a 50% particle diameter (D ₅₀ ) is in one Range of 4 to 24 microns and is a honeycomb porosity of the honeycomb structure produced in a range of 40 to 55%.

The bulk density is obtained by dividing a bulk volume of porous silica by a weight thereof, and it can be measured using a commercially available raw density meter. Further, the 50% particle diameter (D ₅₀ ) is generally referred to as a "mean diameter" and indicates a particle diameter in a case where a relative particle amount based on a particle diameter scale of porous silica in the form of the powder is 50%. becomes.

On the other hand, the honeycomb porosity indicates a porosity of the partitions forming the honeycomb structure. It is to be noted that, in the manufacturing method of the honeycomb structure of the present embodiment, the corresponding honeycomb porosity is one based on mercury porosimetry JIS R1655 corresponds, measured value indicates.

That is, in addition to the above-mentioned determination by two parameters, ie, the amount of the oil to be absorbed and the BET specific surface area of porous silica, the bulk density of porous silica and its 50% particle diameter are further limited and is the range of the honeycomb porosity of the fired honeycomb structure, so that it is possible to manufacture the honeycomb structure which further suppresses an increase in the kneading material / water ratio and prevents the generation of defects such as the partition wall cracks.

In addition, it is possible to stably manufacture the honeycomb structure with a high porosity, and can improve a so-called "light-off performance". Here, the "light-off performance" refers to a developed by a cleaning performance of an impregnated catalyst in the honeycomb temperature behavior.

That is, the honeycomb structure has an excellent behavior that the temperature of the honeycomb structure quickly rises to a temperature at which it is possible to provide a high cleaning performance in a relatively short time from the start of cleaning when cleaning is started by the honeycomb structure becomes. As the porosity of the honeycomb structure increases, a heat capacity decreases, a temperature of the catalyst increases more rapidly, and the light-off performance improves. Thanks to the improvement of the light-off performance, the honeycomb structure produced by the manufacturing method of the honeycomb structure of the present embodiment can provide the high cleaning performance.

Hereinafter, examples of the manufacturing method of the honeycomb structure of the present invention will be described, but the manufacturing method of the honeycomb structure of the present invention is not limited to these examples.

(Examples)

1. Measurement of the properties of silica

First, a variety of types of silica powders were prepared which had various amounts of oil to be absorbed and various BET specific surface areas. Further, various properties such as the amount of the oil to be absorbed, the BET specific surface area, a bulk density, and a 50% particle diameter were measured by the above-mentioned measuring methods or the like. It should be noted that Table 1 shows the results obtained as follows. As shown in Table 1, in the present embodiment, a total of 15 kinds of silica were prepared to prepare honeycomb structures of Examples 1 to 7 and Comparative Examples 1 to 8, respectively. In Comparative Example 1, crystalline silica was prepared, and in the other Examples and Comparative Examples, porous silica was prepared.

2. Preparation of a molding raw material and kneading

As described above, various properties of porous silica were measured, the same amount of porous silica was added to each raw material-forming material containing a cordierite composition in a constant ratio, and the material was kneaded to prepare the extrusion-molding raw material ( a raw material production step). The kneading means that an assistant, water and the like are added to a ceramic molding raw material and the material is kneaded to obtain a plastic kneading material. At this time, an amount of the water to be added to a mixture of the molding raw material and the porous silica was adjusted to obtain the same kneading material hardness. As a result, a variety of mold raw materials with constant kneading material hardness were obtained.

3. Measurement of the kneading material / water ratio

A content of the water contained in the kneaded-form raw material was measured, and a kneading material / water ratio was calculated. That is, the kneading material / water ratio indicates, in a case of defining a total weight of the porous silica and water-containing molding raw material as 100, a ratio of the water in%. Table 1 shows the values of the calculated kneading material / water ratio as follows.

Consequently, in the case where the amount of the porous silica to be absorbed oil was in a range of 50 to 190 ml / 100 g (Examples 1 to 6), the kneading material / water ratio of the molding raw material was approximately in a range of 30% or greater and less than 35%. on the other hand In a case where the amount of the oil to be absorbed was 200 ml / 100 g or more, the kneading material / water ratio was 35% or more, and particularly in a case where the amount of the oil to be absorbed was within a range from 240 to 250 ml / 100 g (Comparative Examples 6 to 8), the kneading material / water ratio increased to 38% or higher. On the other hand, even if the amount of the oil to be absorbed was 250 ml / 100 g or more (Comparative Example 2 or 5), the kneading material / water ratio in a case where the apparent density was 0.10 g / cm ³ or lower , a low value. Consequently, it was confirmed that the amount of oil to be absorbed by a porous silica to be added contributes considerably to the kneading material / water ratio.

4. Formation of a honeycomb shaped body

The molding raw material was extruded using an extruder (an extrusion step). Consequently, the honeycomb formed body was obtained with a plurality of honeycomb-defining lattice-like partitions. In addition, a molding die attached to an extrusion port of the extruder was set to be constant, whereby corresponding points such as honeycomb densities and partition wall thicknesses of the respective honeycomb formed by adding porous silica had the same values. Each extruded honeycomb formed body was dried and further cut into a constant size.

5. firing the honeycomb shaped body and forming a honeycomb structure

The dried and cut honeycomb formed body was placed in a kiln and fired at firing conditions of specified firing temperature and firing time (one firing step). Consequently, it was possible to obtain the honeycomb structure containing a cordierite component (a cordierite honeycomb). In the present embodiment, a total of 15 kinds of honeycomb structures of Examples 1 to 7 and Comparative Examples 1 to 8 were formed. A honeycomb shape of each honeycomb structure was square, the honeycomb density was 46.5 honeycomb / cm ² , the partition wall thickness was 0.089 mm, a diameter was 110 mm, and a length was 97 mm.

6. Measurement of honeycomb pore diameter

As for each of the obtained honeycomb structures, a honeycomb porosity of the partition walls of the honeycomb structure was measured according to mercury porosimetry. Table 1 shows the values of measured honeycomb porosity as follows.

7. Presence / absence of formation of partition cracks

Specifically, in each of the honeycomb structures of Examples 1 to 7 and Comparative Examples 1 to 8, each face was visually confirmed and became the presence / absence of "partition cracks" indicating that, along with the evaporation of water in the molding raw material during drying, shrinkage and deformation of the partitions occurred and parts of the partitions were divided, evaluated. Table 1 shows the evaluation results as follows.

Here, Table 1 shows an example in which there are no partition cracks as "excellent" and shows an example in which partition cracks exist as "insufficient". Thus, in each of the honeycomb structures in which the porous silica satisfying the requirements of the present invention was used and the honeycomb porosity was within the specified range, there were no partition wall cracks and the honeycomb structure had a suitable product quality. On the other hand, the evaluation of the partition wall cracks in each of the honeycomb structures (Comparative Examples 4 to 8) in which the amount of the porous silica to be absorbed oil exceeded 190 ml / 100 g and the kneading material / water ratio was high, gave "insufficient". That is, the amount of oil to be absorbed, the kneading material / water ratio, and the presence / absence of partition cracks are particularly related.

8. Light-off performance

A light-off performance was evaluated based on a residual ratio of total hydrocarbons (THC) of a specific hydrocarbon conversion in a cold phase of the NEDC mode for each honeycomb structure in which a three-way catalyst was impregnated by a known method. In this case, the residual THC ratio of Comparative Example 1 was defined as 1.00 and became, based on this comparative example, an example in which the residual THC ratio was smaller than 0.97 was judged to be "excellent", an example in which the ratio was 0.97 or greater and less than 0.99 was judged to be "good" and became an example in which the ratio was 0.99 or was greater than judged "inadequate". Table 1 shows the measurement results of the residual THC ratio as follows.

Thus, in the honeycomb structures of Examples 1 to 7, the light-off performance was "excellent" or "good". On the other hand, particularly in the honeycomb structure in which the honeycomb porosity was 40% or lower (Comparative Examples 1 to 4), the residual THC ratio was 0.99 or greater and the light-off performance was "insufficient". Further, the light-off performance in the honeycomb structure in Example 7, in which the BET specific surface area was close to an upper limit and the honeycomb porosity was close to a lower limit, was "good". That is, the relationship between the honeycomb porosity and the residual THC ratio (the light-off performance) is recognized.

9. Assessment

In a case where each of the evaluation points of the partition crack and the light-off performance was "excellent", the overall rating was "excellent". On the other hand, in a case where at least one of the scores was "good", the overall score was "good" and was in one. Case in which at least one of the evaluation points was "insufficient", the overall assessment "insufficient". Table 1 shows the results as follows. [Table 1]

10. Relationship between the specific BET surface area and the amount of oil to be absorbed

3 Fig. 12 is a graph showing the BET specific surface area along the abscissa, the amount of the oil to be absorbed along the ordinate, and plotted results of the respective values of Examples 1 to 7 and Comparative Examples 1 to 8, respectively. Consequently, it is believed that in the production process of the honeycomb structure of the present invention, it is possible to suitably use and possible porous silica having the BET specific surface area and the amount of the oil to be absorbed which corresponds to a hatched area in the graph to make the honeycomb structure which has no partition crack and whose light-off performance is excellent.

11. Relationship between kneading material / water ratio and honeycomb porosity

4 FIG. 12 is a graph showing the kneading material / water ratio along the abscissa, honeycomb porosity along the ordinate, and plotted results of respective values of Examples 1 to 7 and Comparative Examples 1 to 8. Accordingly, in the manufacturing method of the honeycomb structure of the present invention, when the kneading material / water ratio of the molding raw material and the honeycomb porosity correspond to a shaded area in the graph, it is considered that it is possible to manufacture the honeycomb structure which does not crack partitions and whose light-off performance is excellent.

A manufacturing method of a honeycomb structure of the present invention is useful in producing a honeycomb structure containing a cordierite component usable in an automobile exhaust gas purifying catalyst carrier, a diesel particulate filter, a heat storage for a combustor or the like.

LIST OF REFERENCE NUMBERS

1

honeycomb structure

2a

a front side

2 B

other front side

3

honeycomb

4

partition wall

5

Honeycomb body

6

Peripheral wall portion

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2016-037845 [0001]
• WO 2005/090263 [0007]

Cited non-patent literature

• JIS K5101-13-1 [0026]
• JIS K5101-13-2 [0026]
• JIS R1626 [0031]
• JIS R1655 [0036]

Claims (5)

A manufacturing method of a honeycomb structure, comprising: a raw material manufacturing step for adding porous silica powder as an inorganic pore-forming agent to a molding raw material and kneading the molding raw material to prepare the kneaded-molding raw material; an extrusion step of extruding the obtained molding raw material to form a honeycomb molded body; and a firing step for firing the extruded honeycomb formed body to form the cordierite component-containing honeycomb structure having partition walls defining a plurality of honeycombs which become passage passages for a fluid and extend from one end face to the other end face, wherein an amount of the porous silica to be absorbed in the porous silica to be added to the molding raw material is in a range of 50 to 190 ml / 100 g and a BET specific surface area of the porous silica is in a range of 340 to 690 m ² / g. The production method of the honeycomb structure according to claim 1, wherein a bulk density of the porous silica is in a range of 0.15 to 0.64 g / cm ³ . The production method of the honeycomb structure according to claim 1 or 2, wherein a 50% particle diameter (D ₅₀ ) of the porous silica is in a range of 4 to 24 μm. A manufacturing method of the honeycomb structure according to any one of claims 1 to 3, wherein a honeycomb honeycomb porosity is in a range of 40 to 55%. The manufacturing method of the honeycomb structure according to any one of claims 1 to 4, wherein in the firing step, the porous silica is melted, reacts with another component contained in the molding raw material to be converted into cordierite, and forms part of the honeycomb structure.

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